1. Technical Field
The present invention relates to the configuration of a micropump that feeds a fluid through an elastic tube by sequentially opening and closing the tube through depression over a plurality of fingers by rotation of a cam.
2. Related Art
A previously-known fluid transfer device is a peristaltic pump that feeds a fluid by squeezing a tube. In the peristaltic pump, the tube is disposed along a platen curved concave, and in the vicinity of the platen and the tube, a cam is disposed. Between the cam and the tube, a plurality of fingers are disposed. With such a configuration, when the cam is rotated, the fingers are responsively depressed sequentially in the direction of the tube, whereby the tube is squeezed and a fluid is fed. With such a fluid transfer device, the platen is attached to the tube body so that the tube is detachably disposed between the fingers and the platen. An example includes Patent Document 1 (JP-T-2001-515557).
With such a peristaltic pump of Patent Document 1, the tube is attached to the concave portion of the platen by insertion, and the resulting platen is then attached to the tube body by insertion, thereby putting the peristaltic pump in a state available for driving. The concern with such a peristaltic pump is that, however, with the tube being disposed between the platen and the fingers, some of the fingers are always closing or depressing the tube. With such a configuration, before driving of such a peristaltic pump, or when the tube remains depressed at any specific portion for a long period of time, e.g., when the pump has been in the halting state, the tube remains deformed, thereby preventing the feeding of the fluid. There is also a problem that any desired amount of flow for feeding cannot be derived because the tube does not return to its original shape.
Herein, although the tube is detachably attached to the pump body, attaching/detaching the tube at the time of driving or stopping may cause operational inconvenience, or may invite human errors at the time of attachment/detachment thereof. Moreover, even if the peristaltic pump is made water resistant, repeating such tube attachment/detachment results in a difficulty for the pump to remain water resistant inside.
Furthermore, when such a peristaltic pump is disposed at a position where such tube attachment/detachment is difficult, e.g., in a living body, the tube is hardly free from deformation and deterioration as described above because the tube remains attached to the pump body.